Rotor construction for rotary regenerator



April 4, 1961 A. HEss 2,978,227

ROTOR CONSTRUCTION FOR ROTARY REGENERATOR 5 Filed July 23, 1958 2Sheets-Sheet 1 April 4, 1961 A. HESS ROTOR CONSTRUCTION FOR ROTARYREGENERATOR Filed July 23, 1958 2 Sheets-Shea?l 2 Anfon H655 I b arqnzjgRoron CONSTRUCTION ron ROTARY REGENERATOR Anton Hess, Parma, lrio,assigner to Thompson Ramo Wooldridge Inc.,fa corporation of Ohio FiledJuly 23, 1958, Ser. No. 750,514 1 claim. (ci. :tsr-26s) This inventionrelates to a regenerator for use with a gasv turbine and moreparticularly to an improved rotary regenerator structure having owpassages therethrough yfor receiving heat from a How of exhaust gas froma turbine and -for heating a flow of compressed air from an aircompressor supplying air-to a combustor for the turbine.

The invention contemplates the provision of a drumtyperotary regeneratorhaving a housing with a partition to divide the housing intocompartments and with an inlet and outlet Ifrom one of the compartments`forthe flow of air from a compressor to a combustor, and an inlet andan outlet in the other compartment for a flow of hot -gases from .aturbine exhaust to the atmosphere. Within the housing is a rotaryannular matrix drum passing through the partition with sealing meanspreventing the lio-w o-f high pressure air from the air compartment tothe low pressure exhaust compartment. The matrix drum includes aplurality of spaced coaxial annular spacer'rings with matrix ringstherebetween formed of half-circle segmentsl and having radiallyextending corrugations which are spot welded to the surfaces of thespacer rings. Coaxial retainer rings are positioned outside of the endspacer rings and receive axially extending spacer rods projectingthrough axial openings-through the assembly. A ring gear for driving thematrix assembly in rotation is secured coaxially to the assembly.

.An object of the present invention is to provide an improved matrixassembly for a rotary regenerator having a large number of gas owpassages and providing improved heat transfer and other advantages overmatrix constructions heretofore used.

Another object of the invention is to provide an improved matrix drumstructure.

Another object of the invention is to provide an irnproved matrixassembly which is capable of being manufactured with improved tolerancesand retaining the tolerances during operation with minimum distortionsof the assembly due to thermal changes.

Another object of the invention is to provide :an improved and morerigid matrix construction which will eliminate unnecessary anddetrimental twisting, warping and non-uniform stressing due to forcesbetween the re= lated parts in manufacturing and in operation withthermal expansion and contraction.

Other objects and advantages will become more apparent with the teachingof the principles of the present invention in connection with thedisclosure of the pre ferred embodiment thereof in the specification,claim and drawings, in which: v

Figure l is Va sectional view shown in somewhat sche-v matic yform lof aturbine assembly employing a rotary regenerator embodying the principlesof the present invention; i

Figure 2 is a perspective View of a rotating matrix drum assemblyembodying the principles of the present invention; f

States er Figure 2a is a horizontal sectional view taken substantiallyalong lines IIa-Ila of Figure l;

Figure 3 is a vertical sectional view taken substantially along lineIII-III of Figure 2;

Figure 4 is an enlarged detailed elevational view showing the matrix andspacer elements in assembled relationship to `define gas llow passages;and

Figure 5 is a perspective View of the matrix land spacer assemblyillustrating the manner of securing the assembly.

As shown on the drawings: i

Figure 1 illustrates a turbine assembly having a turbine section 6 witha turbine housing 8 land a turbine rotor 10 therein. The housing isprovided with a gas inlet 12 supplie-d from a combustor 14 which isprovided with fuel at 16. The turbine rotor is mounted on a shaft :18which is suitably supported on bearings in the turbine housing 8, andwhich drives a compressor 2G. The compressor has a housing 22 with acompressor rotor 24 therein. The compressor rotor is secured to theshaft 18 and draws air through an inlet 26 in the housing 22. The com`pressed air is delivered from the volute-shaped chamber of the housing22 through la compressed air discharge conduit 2S, which connects to aregenerator housing 30.

Within the regenerator housing Si) is a rotary annular shaped drum ormatrix assembly 32 which will be de-` lsame passages alternatelyaccommodating the flow of gas and yair as the matrix assembly is rotatedwithin the housing 3i), as will be appreciated by those skilled in theart; The housing 30 is provided with a partition 34 receiving the drum32 therearoun-d in sealed relation and dividing the housing into acompartment 36 for com pressed air and a compartment 38 for exhaustgases. The partition is provided `with suitable seals shownschematically at 37, which coact with the surface of the drum 32 toprevent the escape of air past the partition from the high pressure aircompartment 36 to the lower pressure exhaust compartment 38. The seal 37is a-lso shown in Figure 2a and extends in substantially a radicaldirection to surround the matrix assembly 32. This seal is substantiallyas shown in the copending application, Hess and Barish, Serial No.750,515, led July 23, 1958. Compressed air ows radially inward throughthe matrix assembly 32 from the compressed air conduit 28 through aregenerator housing inlet 29, and intothe center of the drum incompartment 36 and there out through a regenerator housing outlet 39 andthrough a conduit 40 leading to the combustor. Exhaust gas from theturbine ilows radially outwardly throu-gh the matrix assembly from anexhaust conduit 42 through an exhaust inlet 43 leading into thecompartment 3S of the regenerator housing, and there out through anexhaust outlet 44, leading from the regenerator housing. l

The hot exhaust gas passes radially outward through the portion of thematrix in the compartment 38 and heats the matrix. The drum is rotatedand the heated matrix in passing through the compartment 36 receives thecompressor air therethrough in a radially inward direction to heat theair. Hot air is thus fed to the combustor and since the air is heatedwith exhaust gases from the turbine, the efiiciency of turbine operationis lgreatly improved. Y

Constructional details of the matrix assembly for the regenerator areillustrated in Figures 2 through 5.

The matrix -assembly consists generally of an annul-arly shapeddrumwhich is rectangular in cross-section as illustrated in Figure 3. Asillustrated particularly in Figures 2, 3, 4 and-5, the assembly includesa plurality ofv 3 as illustrated at 46, 47 and 48. Between each of thespacer rings are matrix rings, such as illustratedat 49, 50 and 51.

The spacer rings are preferably' formed with substantially at upper andlower surfaces 48a and 4811 and the rings are annular in shape, having acircular outer edge 48e and a similar circular inner edge 48d. Thespacer rings may be formed of stainless steel or a similar material.

The matrix rings 49, 50 and 51 are formed of circular lribbons ofmaterial with radially extending corruga` tions to form angularconverging walls, such as shown on the ring 50 at 50a and 50b in Figure4, which meet at a ridge 50c and join adjoining walls at ridges 50d and50e.

The matrix elements are attached to the at surfaces of the spacer rings46, 47 and 48 by radially spaced spot welds which may be termed tweezerwelds. As illustrated in Figure 5, a pair of tweezer welds 52 and 54secure the ridge 50d to the flat upper surface 49a of the ring 48.Similar tweezer welds are circumferentially spaced and are used in pairsaround the matrix element to secure it to the spacer ring.

The matrix elements are formed in sections to complete a matrix ring. Asection 50 is illustrated and the sections preferably are semi-circularand butted against an adjacent section to form a complete matrix ring.Thus, radially extending passages will be formed by the corrugationscompletely around the assembly.

The tweezer welding of the matrix sections to the spacer rings servestwo important purposes. First, the at spacer ring prevents the splitmatrix ring from expanding irregularity. The ends of the segment willnot emerge beyond the envelope defined by the end spacer rings 46 and56, as illustrated in Figure 2. These end spacer rings are held betweenlower and upper retaining rings S and 59, which are circular in shapeand positioned coaxial with the assembly to sandwich the matrix elementsand spacer rings therebetween. The retaining of the ends of the matrixelement segments between the envelope defined by the retaining ringsprevents regenerator drum distortion and resultant drum matrixdestruction. The tweezer welds further add rigidity and sectionalstrength to the matrix assembly as it denes the limits. The welding isdone in a symmetrical manner to assure that the matrix assembly expandswith temperature changes with a minimum amount of restriction.

Axially extending shoulder bolts or rods, such as shown at 60 and 62 inFigures 2 and 3, coact to hold the parts of the assembly together andrigidify the structure. The shoulder bolts extend through axially boredholes 64 and 66 through the stacked matrix rings and spacer rings. Theretainer ring 59 is provided with a smaller threaded opening 68 alignedwith the hole 64 to receive the reduced threaded end 60a of the shoulderbolt 60. This provides a shoulder 60h which engages the upper surface ofthe ring. The outer shoulder bolt 62 likewise has a reduced end 62awhich is threaded into an aligned opening 70 in the end retainer ringand which provides a shoulder 62h for engaging the upper surface of theretainer ring.

The upper ends of the bolts project into holes 72 and 74 in the upperretainer ring 59. The bores 72 and 74 are met by counterbores 76 and 78which are smaller in size so as to provide a shoulder to be engaged bythe upper shoulders 60e and 62C. Thus, the distance between the endretainer rings 58 and 59 is positively determined by .the shoulders onthe shoulder bolts.

To the outer surfaces of the retainer ring S9 is attached a ring gear 80for purposes of driving the matrix assembly in rotation. Bushings 82 and84 are threaded onto the upper reduced ends 60d and 62d of the shoulderbolts and recess into openings in the ring gear to positively locate thering gear and draw it tightly against the retainer ring 59 and hold theretainer ring downwardly against the shoulders 60e and 62e in-theshoulder bolts.

` sistant foil.

Locking pins 86 and 88 are inserted into grooves in the sides of thebored openings that receive the bushings so as to lock the bushings inplace and prevent them from rotating loose.

As will be observed in Figure 2, there are a plurality of pairs ofshoulder bolts arranged completely around the matrix assembly beingsubstantially equally spaced in an annular pattern. Since they areidentical in construction with the shoulder bolts 60 and 62, only theseneed be described in detail.

It will be noted that the outer shoulder bolt 62 is positioned to be inthe radial shadow of the inner shoulder bolt 60, and is larger than theinner shoulder bolt. The shoulder bolt arrangement is such as tocompensate for the unequal thermalexpansion of the regenerator drumassembly due to the thermal gradient thereacross. The compensation Vforthis gradient is accomplished by the positioning of the bolts, by theuse of the two sizes of shoulder bolts, and by -providing an outer tboltof a material of a nature so as to meet physical requirements, and inaddition have a coeicient of thermal expansion small enough to allowcompromising. The result of the assembly, in accordance with theinvention, minimizes thermal distortions of the drum assembly.

The lower and upper retaining rings 58 and 59 are heat treated toprovide a near bearing hard load carrying surface on the outer surface,and to provide a tough core. The plates serve the purpose of retainingthe stacked matrix rings and lspacer rings without excessive pressureand prevent the collapse of passages or deformation through excessivecompressive forces.

in construction and assembly of the matrix assembly 32, the matrix rings50 are formed of a corrosion re- The matrix material is precut indeveloped ribbons which are stamped to form the corrugations and by thestamping action will draw itself into a radial corrugated segment havingthe correct inside and outside diameter. It will be understood thatwhile the corrugations are illustrated as preferably extending in aradial direction, that the passages may have varied section geometrieswhich may or may not be radial. Further, the corrugations may be formedsuch as by rolling. Stamping -is the simplest form because the matrixfoil material is not stretched, thereby maintaining a constant passagewall thickness and, at the same time, the corrugation base to crownheight tolerance is more easily maintained. This dimensional tolerancemust be `held to very close limits in order to prevent Igas blow byacross whatever seal design may be used. The foil ribbon of material forthe matrix is preferably thin as, for example, on the order of .002"thick. The corrugation size that has proven advantageous has a height of.034 -with .052"

pitch. Separator rings vmay also be formed of thin material, such as.002" thick.

The corrugated half-circle segments are assembled by stacking, and arebutt joined. The assembled stack of matrix rings and separator rings areprovided with holes for the shoulder bolts by drilling and reaming thestacks. The contour may be finished by special grinding procedures, suchas new techniques which employ electrolytic disintegration, using acharged rotating copper disc in place of the usual grinding wheel. Thisyields corrugations that are free from burrs which would reduce the sizeof the corrugated ilow passages. The segments then are tweezer welded tothe spacer rings.

Thus, it will be seen that I have provided an improved matrixconstruction for use in a rotary regenerator for a turbine engine or thelike, which meets the objectives and advantages hereinbefore set forth.The mechanism has features which enable it to withstand the severeeffects of temperature change, the effects of pressure flow through thepassages, and the construction accomplishes j an improved regeneratormechanism.

I have, in the drawings and specifications, presented a detaileddisclosure of the preferred embodiments of 5 um' i my invention, and itis to be understood that I do not intend to limit the invention to thespecific form disclosed, but intend to cover all modifications, changesand alternative constructions and methods falling Within the scope ofthe principles taught by my invention.

I claim as my invention:

A regenerator structure fora gas turbine or the like comprising aplurality of vspaced at surfaced circular continuous circumferentiallyand axially, rigid uninterrupted one piece spacer members, a pluralityof circular` matrix members located between the spacer members andshaped to form substantially radially extending gas flow passagestherethrough, means defining a plurality of circumferentially spacedannularly arranged axially extending outer openings through said spacerand said matrix members, means defining a plurality of innercircumferentially spaced annularly arranged axially extending open- 10rotation through said compartments.

References Cited in the file of this patent UNITED STATES PATENTS 151,843,252. Toensfeldt Feb. 2, 1932 2,313,081 Ljungstrom Mar. 9. 19432,888,248 Bubniak et al. Mar. 26, 1959

